An electrocardiogram, often abbreviated as ECG or EKG, is used to monitor the electrical activity of the heart. There are many different patterns that can be seen in the EKG rhythms that can give vital information to doctors and paramedics. Variations in the EKG rhythms can point to problems with different parts of the heart and can help medical professionals provide the correct treatment.
Normal EKG rhythms consist of a three sections: the P wave, the QRS complex, and the T wave. The P wave is triggered by the contraction of the atrium and sends an electrical impulse to the ventricle to beat. The contraction of the ventricle is seen as the QRS complex, which appears as a sharp spike and corresponds to the noticeable feeling of the heartbeat or pulse. The T wave follows this contraction and happens as the heart gets ready to beat again. Some patients may also have a U wave, which has the same purpose as the T wave.
Abnormalities in EKG rhythms can show problems in the electrical activity of the heart. Many of these problems are not dangerous to the patient, though some of them are indicative of serious medical conditions. An evaluation of the EKG can tell health care workers a great deal about the state of the heart.
Three common abnormalities in EKG rhythms are supraventricular tachycardia, sinus tachycardia, and sinus bradycardia. In supraventricular tachycardia the heart rate is between 140 and 220 beats per minute but is otherwise normal. Patients with sinus tachycardia have a normal rhythm in their heart rate, though the heart is beating at a rate higher than 100 minutes. This is normal if a person has been exercising, is ill, or is stressed. Sinus bradycardia refers to a normal looking EKG with a heart rate of less than 60 beats per minute.
There are a number of EKG rhythms that require immediate medical attention. An EKG that does not show any electrical activity is known as a flat line and means that the heart is not beating. Contraction impulses that generate from the ventricle can sometimes lead to a rapid heartbeat known as ventricular tachycardia. This rhythm may cause the patient to lose a pulse and in such a case the heart would require electrical stimulation. Ventricular fibrillation is similar to ventricular tachycardia but is highly irregular and requires immediate defibrillation.
Problems with the electrical impulses in the atrium can cause atrial flutters or atrial fibrillation, both of which can disrupt the interval of the QRS complex, leading to an irregular or rapid heartbeat. A delay in the transmission of the electrical signal from the atrium to the ventricle can also lead to irregular EKG rhythms. For most such blocks in electrical signals, the atrium still signals the ventricle, though the ventricle is capable of triggering its own contraction if there is a severe block in electrical energy.